The present invention is directed to the art of radiographic medical imaging and, more particularly, to a robotic support system for positioning an x-ray source and receptor pair relative to an examination region to generate and transmit an x-ray beam through the examination region. The invention finds particular application in conjunction with imaging or interventional procedures that have heretofore been performed in association with C-arm or L/U-arm fluoroscopic x-ray systems and will be described with particular reference thereto. It is to be appreciated, however, that the invention is also applicable to a wide range of other medical or industrial imaging apparatus that operate through the use of spaced apart radiographic energy source and receptor pairs to monitor or image a region of a patient or other item disposed between the source and receptor pair.
In some operating rooms, such as operating rooms for vascular catheter procedures, a projection x-ray imaging device is provided in association with an operating table. More specifically, an x-ray tube or generator and an x-ray detector are mounted on a C-arm which is positioned such that a patient or an area of interest lies between the x-ray source and receptor. The x-ray source and receptor are rotatable and longitudinally displaceable as a unit to select a region and angle for projection imaging. Once the surgeon has positioned the x-ray source and detector in the proper position, the surgeon actuates the x-ray tube sending x-rays through the patient and onto the x-ray detector for a preselected exposure time. The x-rays received by the detector are converted into electric video image data signals representing a projection or shadow-graphic image. The projection or shadow-graphic image is stored electronically or displayed on a video monitor which is viewable by the physician.
One such prior art imaging system is shown in FIG. 1. As illustrated, a C-arm C is supported by a curved support carriage A adjacent an examination region E. The examination region E is describable by orthogonal axes X, Y, and Z. An x-ray transparent couch 10 is positioned such that a region of interest of a subject lying upon the couch is positioned in the examination region E.
The rotational support assembly A includes a rotational mount or bearing 14 mounted to a fixture for rotation about a horizontal axis X. The rotational mount 14 can be movably fixed to a track or other mechanism 18 to also allow movement of the mount in the Y and Z directions.
The midpoint 22 of the C-arm C is rotatably attached to the bearing 14. The C-arm C defines two opposing parallel ends 24, 26 on either side of the examination region E. A detector 28, such as a flat panel detector or the like for detecting x-ray radiation, is attached to the first end 24. Common detectors include solid state devices, such as a grid of amorphous silicon detector elements for generating x-ray intensity signals for each element on the grid. An x-ray source 30 is attached on the second end 26 of the C-arm. The C-arm C has sufficient size and bulk to maintain the detector 28 and the x-ray source 30 within a fairly repeatable fixed spatial relationship.
In the system shown, the curved support carriage A is adapted to permit rotational movement of the x-ray source and detector along an arcuate path B to enable left and right anterior oblique image views to be collected. The bearing mount 14 enables cranial and caudal image views to be collected. Compound anterior oblique, cranial, and caudal views can be collected by moving the mechanical C-arm system C carriage support and bearing mount into the appropriate respective orientations.
Due to the mass of the x-ray tube and the weight of the detector carried on opposite ends of the C-arms, the curved support assembly is designed to provide adequate support and rigidity and, therefore, is large and bulky. Similarly, the C-arm assembly C is necessarily large in order to enable head to toe imaging capabilities of a patient disposed between the x-ray source and detector.
During most interventional procedures, the C-arm and curved support carriage A obstruct access to the patient because of their size. The awkwardness of the mechanical support system can cause confusion in the operating room when the surgical procedure requires gross movements of the components such as, for example, when it is necessary to first image the head area, followed by an image of the foot area of the patient. Using the above mechanical system it is also awkward and inconvenient to rotate the C-arm C from the vertical orientation shown in FIG. 1 to either the left or right anterior oblique views.
It is therefore desirable to provide a virtual C-arm support system that has all of the functionality of the prior C-arm system described above, including the carriage and orbit motions, but without the bulky and inconvenient overhead rotational support assembly or the C-arm member rotatably attached to the support assembly.
The present invention provides a new and improved method and apparatus which overcomes the above referenced problems in the prior art and others by eliminating the inconvenient overhead support arm and C-shaped structures found in the prior art systems.